La Sonnaz (French pronunciation: [la sɔna]) is a municipality in the district of Sarine in the Canton of Fribourg in Switzerland . The municipality was created in 2004 through the merger of Cormagens , La Corbaz and Lossy-Formangueires . The municipal administration, the kindergarten and the primary school are in Lossy.

La Sonnaz has an area, as of 2009, of 6.9 square kilometers (2.7 sq mi). Of this area, 4.58 km2 (1.77 sq mi) or 66.4% is used for agricultural purposes, while 1.53 km2 (0.59 sq mi) or 22.2% is forested. Of the rest of the land, 0.51 km2 (0.20 sq mi) or 7.4% is settled (buildings or roads), 0.28 km2 (0.11 sq mi) or 4.1% is either rivers or lakes.